This invention is concerned with a method for generating hydrogen, particularly for generating hydrogen for fuel cells.
In U.S. Pat. Application Ser. No. 397,009, filed Sept. 13, 1973, now U.S. Pat. No. 3,932,600, issued Jan. 13, 1976, and German Offenlegungsschrift 2,244,944 (page 11, claims 1 to 3), a method for the generation of hydrogen, particularly hydrogen for fuel cells, is described by the reaction of metals with water. According to the disclosures the process comprises reacting with water particles of magnesium metal or a combination of magnesium and aluminum metal, such particles being admixed with an oxide of cobalt and the reaction which generates the hydrogen occurring in the presence of a watersoluble chloride. The disclosed method permits generation of hydrogen in a simple manner, and it requires neither the use of acids or alkaline solutions for the decomposition of the metals, nor the use of substances such as mercury for activating the metals through amalgamation. Magnesium and aluminum are advantageously used in a weight ratio of about between 7:1 and 2:6, and preferably between about 5:3 and 3:5. The cobalt oxide is added to the metal or the metal mixture in an amount which is preferably between 0.5 and 5% by weight, based on the metal. The amount of chloride used is preferably in the range between 5% and 200% by weight, based on the metal content. Fillers can be added to the metal which prevent agglomeration of the metal particles and ensure hydrolysis of the metal to a large extent. Any or a mixture of cobaltous oxide (CoO), cobaltic oxide (Co.sub.2 O.sub.3) and tricobalt tetraoxide (Co.sub.3 O.sub.4) may be employed. Particularly good results are obtained with Co.sub.2 O.sub.3 and Co.sub.3 O.sub.4, especially with Co.sub.3 O.sub.4.
The water-soluble chloride is preferably sodium chloride. Other suitable chlorides are, for instance, potassium chloride and magnesium chloride.
The chloride can be added to the metal or the metal mixture but it can also be dissolved in the water. Sea water is advantageously used as the aqueous chloride solution. Sea water generally contains a total of about 3.5% salts, predominantly in the form of chlorides; the major quantity being sodium chloride which constitutes about 2.7% by weight.